The perfect place for a man cave
Planet hunters have always been keen to find Earth's twin, but an astrobiology team now suggests that "superhabitable" planets may be even better places to look for alien life.
In the journal Astrobiology, however, researchers René Heller of Canada's McMaster University and John Armstrong of Weber State University in Ogden, Utah, calls that idea too Earth-focused. "From a potpourri of habitable worlds that may exist, Earth might well turn out as one that is marginally habitable, even bizarre from a biocentric standpoint," they write.
Instead, they suggest that astronomers should focus their planet hunting on worlds that might harbor conditions even more amenable to life. The authors dub these hypothetical worlds "superhabitable." (See "Think Outside the Box to Find Extraterrestrial Life.")
Their report adds to a chorus of voices in the planet-hunting community that have called for rethinking the idea of "habitable zones" where worlds that follow orbits friendly to oceans and life would exclusively exist.
Worlds Waiting
When NASA launches the James Webb Space Telescope in 2018, it may help scientists to take a closer look at a planet's atmosphere, detect if it has oceans, and analyze its chemical composition.
If superhabitable planets exist, and if we develop the means to find them, they may turn out to be more common than Earthlike planets—current studies suggest that super-Earths are more common than Earth-size planets (although those studies may be biased by the fact that it's easier to spot larger planets).
The concept of superhabitability could broaden our chances of discovering life on other worlds, Kopparapu says, "because it opens up the possibility that there may be some super-Earth planets with appropriate conditions for life ... I think it is noteworthy to consider these planets for future habitability studies."
